The present invention relates generally to the field of image forming apparatuses and in particular to an image forming apparatus with an integrated media input tray including electronics.
Many image forming apparatuses; copiers; multi-function machines, i.e., those that combine two or more functions such as fax, scan, copy, and print; and the like (all of which are encompassed herein by the term “image forming apparatus”), contain one or more primary media trays that an end user removes from the machine to load with a stack of media sheets, such as print paper. The uppermost sheet in the stack is selected, or “picked” from the stack by the image forming apparatus. In some image forming apparatuses, one tray is inserted into a single receptacle in the image forming apparatus, the tray selected from a plurality of removable trays, each configured to hold different size and/or type of media sheets. Other image forming apparatuses accept a plurality of removable media input trays simultaneously into different receptacles.
In addition, many image forming apparatuses include a Multi-Purpose Tray (MPT), a separate media sheet input that is used to feed specialty media such as transparencies, envelopes, and the like. In some image forming apparatuses these specialty media are input manually, one media sheet at a time. Other image forming apparatuses pick specialty media from a small stack at an MPT input. In some image forming apparatuses, the MPT input is also removable from the image forming apparatus.
Traditionally each of these media input trays mates with a media sheet pick mechanism, such as for example an autocompensator, located in the base image forming apparatus. The pick mechanism operates to select and separate one media sheet (usually the uppermost sheet) from a stack of media sheets in the tray, and feed the selected sheet into the print mechanism in the image forming apparatus. The pick mechanism is driven by a motor, which is connected to the pick mechanism by a drive train. Both the motor and the drive train are traditionally located in the image forming apparatus.
Prior art removable media input trays also may include a variety of media sensors (and/or configurable surfaces operative to trigger sensors located in the image forming apparatus) that sense, for example, media size, media near empty, transparency sensing, and media in the paper path. A large plurality of sensors, particularly if required on each of two or more removable media input trays, increases costs and reduces reliability by proliferating the number of potential failure points.
Conventional removable media input trays present several disadvantages. Because the pick mechanism, drive train, and motor are housed in the image forming apparatus, and media sheets are picked from a stack located in the tray, the drive force of the pick tire exerted on the media stack tend to push the tray out of the image forming apparatus. To combat this force, and avoid the media input tray being dislodged from the image forming apparatus, many removable media input trays include detents or other pliable surfaces that deform slightly upon insertion and removal of the tray from the image forming apparatus, thus “latching” the tray to the image forming apparatus when inserted. These securing mechanism add cost and complexity to the tray, make it more difficult to use by requiring greater force to insert or remove the tray, and decrease reliability as the pliable surfaces may break off from the tray in use.
In prior art image forming apparatuses including both a primary media input tray and an MPT input, the MPT input is typically located above the primary media input tray (to facilitate removal of the primary media tray). This necessarily increases the overall height of the image forming apparatus. In addition, if the same motor is used to drive pick mechanisms for both the primary media input tray and the MPT input, a complex drive train having a compliant member such as a swing arm clutch is required to break the drive train, such that the image forming apparatus can operate when one or the other of the primary media input tray and the MPT input are removed. Such a drive train adds cost and complexity to the image forming apparatus, and may further increase the undesirable dislodging force(s) exerted on the removable tray(s). Additionally, locating part of the paperfeed mechanism in the image forming apparatus and part in the removable tray increases the difficulty and cost of troubleshooting and servicing failed components.